Instructional Video
Khan Academy

Khan Academy: Geometry: Angles Formed by Parallel Lines and Transversals

For Students 9th - 10th Standards
Identifies which angles are congruent when parallel lines are cut by a transversal. [7:07]
Instructional Video
Khan Academy

Khan Academy: Geometry: Angles of Parallel Lines 2

For Students 9th - 10th Standards
Explains how to determine the measures of all the angles formed when parallel lines are cut by a transversal based on the measure of one angle. Explains how to use corresponding congruent angles to determine if lines cut by a transversal...
Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: Deductive Reasoning

For Students 9th - 10th Standards
Demonstrates solutions to problems #1-3 of California Geometry released state test questions. Problems address understanding of deductive reasoning and congruent angles created by parallel lines cut by a transversal. [10:17]
Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: More Proofs

For Students 9th - 10th Standards
Demonstrates solutions to problems #7-10 of California Geometry released state test questions. Problems address understanding of congruent angle pairs when parallel lines are cut by a transversal, counterexamples, and properties of the...
Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: Triangles and Parallelograms

For Students 9th - 10th Standards
In this video lesson [11:14], the instructor demonstrates solutions to problems #21-25 of California Geometry released state test questions. Problems address understanding of the triangle inequality theorem, angle relationships with...
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof Sum of Measures of Angles in a Triangle Are 180

For Students 9th - 10th
Proof that the sum of the angles in a triangle is 180 using the relationship of angles formed when parallel lines are cut by a transversal. This video also appears in the Geometry: Triangles strand. [6:31]
Instructional Video
Khan Academy

Khan Academy: Geometry: Angles (Part 3)

For Students 9th - 10th Standards
Identifies and defines the types of angles formed by parallel lines cut by a transversal and the relationship of their measures. Discusses Triangle Sum Theorem. [9:48]
Instructional Video
Shmoop University

Shmoop: Parallel Lines and Transversals

For Students 9th - 10th Standards
A video clip showing parallel lines and transversals. Using everyday items to familiarize the student with the concept.
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Find Missing Angles in a Transversal Diagram?

For Students 9th - 10th Standards
Take a look at this tutorial to see how to find all the missing angle measurements by identifying vertical, corresponding, adjacent, and alternate exterior angles. [4:43]
Instructional Video
Khan Academy

Khan Academy: Geometry: Finding More Angles

For Students 9th - 10th Standards
Solving for measures of the angles in a triangle using algebra, the triangle sum theorem, and properties of angles created by a transversal that cuts parallel lines. [6:05]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Sides of Parallelogram Congruent

For Students 9th - 10th Standards
Demonstrates how to prove that the opposite sides of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [8:30]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Opposite Angles of Parallelogram Congruent

For Students 9th - 10th Standards
This video tutorial demonstrates how to prove that the opposite angles of a parallelogram are congruent based on knowledge of the special angles created when parallel lines are cut by a transversal. [4:08]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof: Diagonals of Parallelogram Bisect Each Other

For Students 9th - 10th Standards
Demonstrates how to prove that the diagonals of a parallelogram bisect each other based on knowledge of the special angles created when parallel lines are cut by a transversal and the triangle congruency postulates. [9:06]
Instructional Video
Khan Academy

Khan Academy: Geometry: Triangle Angle Example 2

For Students 9th - 10th Standards
Shows how to find the measure of missing angles using the triangle sum theorem and vertical angles. This video also appears in the Geometry: Triangles strand. [4:55]
Instructional Video
Khan Academy

Khan Academy: Geometry: Similar Triangles

For Students 9th - 10th Standards
Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals. [9:34]
Instructional Video
Khan Academy

Khan Academy: Geometry: Angles Formed Between Transversals and Parallel Lines

For Students 9th - 10th Standards
Explains the relationship between the measures of angles formed when parallel lines are cut by a transversal based on relationships of corresponding, vertical, and supplementary angles. [7:53]
Instructional Video
Khan Academy

Khan Academy: Geometry: Example Involving Isosceles Triangle and Parallel Lines

For Students 9th - 10th Standards
Demonstrates how to use the triangle sum theorem, properties of isosceles triangles, and special angle pairs formed when parallel lines are cut by a transversal to set up an equation using given algebraic expressions for angle measures...
Instructional Video
Khan Academy

Khan Academy: Geometry: Similar Example Problems

For Students 9th - 10th Standards
Explains how to identify and use similar triangles in order to determine unknown side lengths in two given diagrams. Each diagram also applies knowledge of angles formed when parallel lines are cut by a transversal. [7:37]
Instructional Video
Study Pug

Study Pug: Perpendicular Line Proofs

For Students 9th - 10th Standards
Video lesson explains angles, lines, and transversals. [9:33]
Instructional Video
Khan Academy

Khan Academy: Triangles: Intro to Triangle Similarity

For Students 9th - 10th Standards
Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals.